Wiring substrate and its manufacturing method

Abstract

A wiring substrate having, on a surface, a mounting pad for mounting a semiconductor device comprises a metal pad, an insulating layer, and a metal layer. A pad area of the mounting pad is defined by an opening section formed in the insulating layer. The wiring substrate further comprises an etching barrier layer provided between an upper surface of the metal pad and the insulating layer. The etching barrier layer is provided to surround a lower end of the opening section and extends outward from the lower end of the opening section to the outer periphery.

1 . A wiring substrate having, on a surface, a mounting pad for mounting a semiconductor device, the wiring substrate comprising:
 a metal pad provided on one of main surfaces of a base material;   an insulating layer being provided to cover a side surface of the metal pad and at least part of an upper surface of the metal pad, and being provided with an opening section that exposes a part of the upper surface of the metal pad; and   a metal layer provided on the metal pad exposed through the opening section, wherein   a pad area of the mounting pad is defined by the opening section formed in the insulating layer, and   the wiring substrate further comprises an etching barrier layer provided between the upper surface of the metal pad and the insulating layer, the etching barrier layer being provided to surround a lower end of the opening section and extending outward from the lower end of the opening section toward an outer periphery.   
     
     
         2 . The wiring substrate according to  claim 1 , wherein at least an end of the etching barrier layer on the opening section side is in contact with the metal layer. 
     
     
         3 . The wiring substrate according to  claim 1 , wherein the etching barrier layer is made of a metal different from a metal of which the metal pad is made. 
     
     
         4 . The wiring substrate according to  claim 1 , wherein the etching barrier layer is made of an inorganic material. 
     
     
         5 . The wiring substrate according to  claim 1 , wherein an end of the etching barrier layer on the opening section side protrudes toward a center of the opening section, relative to an inner peripheral surface of the opening section. 
     
     
         6 . The wiring substrate according to  claim 1 , wherein the etching barrier layer extends to an outer peripheral side edge of the metal pad and covers the side surface of the metal pad. 
     
     
         7 . The wiring substrate according to  claim 1 , wherein an end of the etching barrier layer on the opening section side is located at the lower end of the opening section. 
     
     
         8 . A manufacturing method of a wiring substrate having, on a surface, a mounting pad for mounting a semiconductor device, the manufacturing method includes steps of:
 forming an etching barrier layer on a metal pad provided on one of main surfaces of a base material;   forming an insulating layer covering a side surface of the metal pad and at least part of an upper surface of the metal pad, and being provided with an opening section that exposes a part of the upper surface of the metal pad; and   forming a metal layer on the metal pad exposed through the opening section, wherein   a pad area of the mounting pad is defined by the opening section formed in the insulating layer, and   the etching barrier layer is formed to surround a lower end of the opening section and extend outward from the lower end of the opening section toward an outer periphery.   
     
     
         9 . The manufacturing method of the wiring substrate according to  claim 8 , wherein the metal layer is formed to be in contact with at least an end of the etching barrier layer on the opening section side. 
     
     
         10 . The manufacturing method of the wiring substrate according to  claim 8 , wherein the etching barrier layer is made of a metal different from a metal of which the metal pad is made. 
     
     
         11 . The manufacturing method of the wiring substrate according to  claim 8 , wherein the etching barrier layer is made of an inorganic material. 
     
     
         12 . The manufacturing method of the wiring substrate according to  claim 8 , wherein an end of the etching barrier layer on the opening section side is formed to protrude toward a center of the opening section, relative to an inner peripheral surface of the opening section. 
     
     
         13 . The manufacturing method of the wiring substrate according to  claim 8 , wherein the etching barrier layer is formed to extend to an outer peripheral side edge of the metal pad and cover the side surface of the metal pad. 
     
     
         14 . The manufacturing method of the wiring substrate according to  claim 8 , wherein an end of the etching barrier layer on the opening section side is formed to locate at the lower end of the opening section.